One might say "World's Best Boss" (3)

I believe the answer is:

mug

(Other definitions for mug that I've seen before include "Large drinking vessel or slang victim" , "Make a face" , "Idiot" , "Tankard" , "Charlie" .)

I've seen this clue in the Universal.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.